Managing the Ipswich River water take

The Ipswich River Part II. Last week’s story focused on the river’s health and its recovery from last year’s drought. This week’s story looks at municipal policy that withdraws water from the river.

It’s not so much how much water communities take from the Ipswich River and its watershed.

It’s when.

Summer is worst time to take water from the river because that’s when it flows the least, but that’s when communities draw the most.

That’s the point Wayne Castonguay, executive director of the Ipswich River Watershed Association, makes following a draft report from six of the 14 communities that draw water from the Ipswich River watershed.

The draft report focuses on ways to reduce the overall take from the river watershed and to control the timing of the take.

Castonguay and Jennifer Pederson, executive director of the Massachusetts Water Works Association, sometimes disagree on the numbers of how much water communities take from the river and its watershed, but agree on the draft report’s overall recommendations:

See if some communities can go the Massachusetts Water Resources Authority for water;Increase reservoir storage in the watershed;Reduce “wastewater export” from the watershed -- wastewater taken from the river and its watershed should go back to its source after purification rather than to another system;Increase public water-use education to reduce water use.

Danvers, Hamilton, the Lynnfield Center Water District, Middleton, Topsfield and Wenham received a grant and commissioned the draft report released in late July.

Hydraulically challenged

Overall, the Ipswich River is “hydraulically challenged,” as Pederson said.

That is, the river often drops below its ecologically sustainable flow of 53 cubic feet per second. The river normally flows at half that rate, 25 cubic feet per second, in summer. Last year, during the drought, the river had a negative flow through August and into early autumn. This year, an abnormally wet year, the Ipswich River flows at 78 feet per second.

“Yes, the river is naturally droughty,” Gastonguay said. “It’s super sensitive to water withdrawals by humans. And the amount of water we remove from the river is vital because we have small aquifers.”

Overall, the human take from the river and its watershed is about 7 percent of its total flow. The rest goes out sea, evaporates or is used by plants and trees along the river.

“Forty-five percent evaporates or gets used by plants and trees. Another 48 percent gets recharged into the ground or goes into the stream flow,” said Pederson.

Exactly how much water municipalities withdraw from the Ipswich River remains a point of contention.

The state passed the Water Management Act in 1986, which allowed communities to register their withdrawals with the state.

Total annual withdrawal was almost 30 million gallons a day from 1981 through 1986, and communities were allowed to maintain their reported withdrawal levels.

Pederson points out communities have reduced reported withdrawals: In 2015 the reported withdrawal was 20.52 million gallons a day.

That’s correct said Castonguay, as far as the numbers go.

The reported withdrawals fail to record withdrawals of 100,000 gallons per day or less. “That’s a lot of water,” Castonguay said. An average swimming pool takes 25,000 gallons to fill. The average person uses 65 gallons a day.

Include the unreported withdrawals and the take is back around 30 million gallons per day, Castonguay said, with daily summer take about 50 percent more.

Most of the unreported withdrawals come from smaller business and residential developments -- condominiums, business parks and other commercial developments all using private wells.

Ipswich Town Meeting voted in May to include private wells in any water restrictions the town’s Water Department imposed.

“The study shows there’s enough water for future growth,” Pederson said. “But the ability to get more groundwater is limited.”

Private wells

The private wells are important, said Castonguay, who pointed out North Reading, Wilmington and Middleton combined increased private wells drawing from the Ipswich River watershed by 3,000 over the last 17 years.

So managing that 7 percent human take becomes vital to the river’s overall health and flow.

Pederson cautioned some of the solutions, notably going to the MWRA or increasing reservoir storage, will cost money, and lots of it.

“This isn’t cheap,” Pederson said.

MWRA buy-in costs “several million dollars.” The MWRA also charges a higher per-gallon cost than communities pay now. And that cost doesn’t include the price to increase reservoir capacity.

Currently, Ipswich, Beverly-Salem and Danvers use reservoir storage to meet some of their water demand -- reservoir take generally occurs in winter when the river flows strongly and prevents taking water in summer when river flow is low.

The state Legislature passed the water infrastructure bill in 2014 to encourage communities to take a regional approach to solving water supply issues, and offers matching grants for such investment.

Problem is, the Legislature has yet to fund the measure, Pederson said.

Castonguay said not all solutions need to cost millions. Two steps, he argues, would keep the river flowing even during the driest droughts:

Reduce lawn watering to once a week and have people plant less thirsty fescue grass instead of blue grass.

Reduce the wastewater take from Ipswich River and its watershed by returning some of the wastewater, once treated, back to the river.

“Most of the water taken from the basin, 80 percent, is wastewater,” said Castonguay. “That’s the real problem. If we could cut that in half, the river would never run dry.”